For all types of substrates, magnetic recording media has begun to incorporate perpendicular magnetic recording (PMR) technology in an effort to increase magnetic recording areal density. Although magnetic recording areal densities of approximately 1 Tb/in2 have been achieved, further increases are unlikely as the physical limits of PMR have nearly been met due to the superparamagnetic effect. Accordingly, Heat-assisted magnetic recording (HAMR) technology has been developed to meet the growing demand for improved magnetic disk drive data capacity.
HAMR media is often made of magnetic materials or compounds with a substantially higher magnetocrystalline anisotropy than that of non-HAMR media. Because HAMR media is made of higher-stability magnetic compounds, HAMR media relies upon the application of heat to achieve changes in magnetic orientation. That is, HAMR media is temporarily heated to reduce its coercivity below that of an applied magnetic write field from a recording head. These materials can store bits in a much smaller area without being limited by the superparamagnetic effect. In this regard, HAMR technology is a promising solution for pushing the magnetic recording areal density of a hard disk to beyond 1 Tbit/in2.